/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.feilong.lib.beanutils;

import java.io.Serializable;
import java.lang.reflect.Constructor;
import java.lang.reflect.InvocationTargetException;
import java.util.HashMap;

import org.apache.commons.beanutils.DynaBean;

/**
 * <p>
 * Minimal implementation of the <code>DynaClass</code> interface. Can be
 * used as a convenience base class for more sophisticated implementations.
 * </p>
 * *
 * <p>
 * <strong>IMPLEMENTATION NOTE</strong> - The <code>DynaBean</code>
 * implementation class supplied to our constructor MUST have a one-argument
 * constructor of its own that accepts a <code>DynaClass</code>. This is
 * used to associate the DynaBean instance with this DynaClass.
 * </p>
 *
 * @version $Id$
 */

public class BasicDynaClass implements DynaClass,Serializable{

    // ----------------------------------------------------------- Constructors

    /**
     * 
     */
    private static final long serialVersionUID = 6170153721746209026L;

    /**
     * Construct a new BasicDynaClass with default parameters.
     */
    public BasicDynaClass(){

        this(null, null, null);

    }

    /**
     * Construct a new BasicDynaClass with the specified parameters.
     *
     * @param name
     *            Name of this DynaBean class
     * @param dynaBeanClass
     *            The implementation class for new instances
     */
    public BasicDynaClass(final String name, final Class<?> dynaBeanClass){

        this(name, dynaBeanClass, null);

    }

    /**
     * Construct a new BasicDynaClass with the specified parameters.
     *
     * @param name
     *            Name of this DynaBean class
     * @param dynaBeanClass
     *            The implementation class for new intances
     * @param properties
     *            Property descriptors for the supported properties
     */
    public BasicDynaClass(final String name, Class<?> dynaBeanClass, final DynaProperty[] properties){

        super();
        if (name != null){
            this.name = name;
        }
        if (dynaBeanClass == null){
            dynaBeanClass = BasicDynaBean.class;
        }
        setDynaBeanClass(dynaBeanClass);
        if (properties != null){
            setProperties(properties);
        }

    }

    // ----------------------------------------------------- Instance Variables

    /**
     * The constructor of the <code>dynaBeanClass</code> that we will use
     * for creating new instances.
     */
    protected transient Constructor<?>      constructor       = null;

    /**
     * The method signature of the constructor we will use to create
     * new DynaBean instances.
     */
    protected static Class<?>[]             constructorTypes  = { DynaClass.class };

    /**
     * The argument values to be passed to the constructore we will use
     * to create new DynaBean instances.
     */
    protected Object[]                      constructorValues = { this };

    /**
     * The <code>DynaBean</code> implementation class we will use for
     * creating new instances.
     */
    protected Class<?>                      dynaBeanClass     = BasicDynaBean.class;

    /**
     * The "name" of this DynaBean class.
     */
    protected String                        name              = this.getClass().getName();

    /**
     * The set of dynamic properties that are part of this DynaClass.
     */
    protected DynaProperty[]                properties        = new DynaProperty[0];

    /**
     * The set of dynamic properties that are part of this DynaClass,
     * keyed by the property name. Individual descriptor instances will
     * be the same instances as those in the <code>properties</code> list.
     */
    protected HashMap<String, DynaProperty> propertiesMap     = new HashMap<>();

    // ------------------------------------------------------ DynaClass Methods

    /**
     * Return the name of this DynaClass (analogous to the
     * <code>getName()</code> method of <code>java.lang.Class</code), which
     * allows the same <code>DynaClass</code> implementation class to support
     * different dynamic classes, with different sets of properties.
     *
     * @return the name of the DynaClass
     */
    @Override
    public String getName(){

        return (this.name);

    }

    /**
     * Return a property descriptor for the specified property, if it exists;
     * otherwise, return <code>null</code>.
     *
     * @param name
     *            Name of the dynamic property for which a descriptor
     *            is requested
     * @return The descriptor for the specified property
     *
     * @throws IllegalArgumentException
     *             if no property name is specified
     */
    @Override
    public DynaProperty getDynaProperty(final String name){

        if (name == null){
            throw new IllegalArgumentException("No property name specified");
        }
        return propertiesMap.get(name);

    }

    /**
     * <p>
     * Return an array of <code>ProperyDescriptors</code> for the properties
     * currently defined in this DynaClass. If no properties are defined, a
     * zero-length array will be returned.
     * </p>
     *
     * <p>
     * <strong>FIXME</strong> - Should we really be implementing
     * <code>getBeanInfo()</code> instead, which returns property descriptors
     * and a bunch of other stuff?
     * </p>
     *
     * @return the set of properties for this DynaClass
     */
    @Override
    public DynaProperty[] getDynaProperties(){

        return (properties);

    }

    /**
     * Instantiate and return a new DynaBean instance, associated
     * with this DynaClass.
     *
     * @return A new <code>DynaBean</code> instance
     * @throws IllegalAccessException
     *             if the Class or the appropriate
     *             constructor is not accessible
     * @throws InstantiationException
     *             if this Class represents an abstract
     *             class, an array class, a primitive type, or void; or if instantiation
     *             fails for some other reason
     */
    @Override
    public DynaBean newInstance() throws IllegalAccessException,InstantiationException{

        try{
            // Refind the constructor after a deserialization (if needed)
            if (constructor == null){
                setDynaBeanClass(this.dynaBeanClass);
            }
            // Invoke the constructor to create a new bean instance
            return ((DynaBean) constructor.newInstance(constructorValues));
        }catch (final InvocationTargetException e){
            throw new InstantiationException(e.getTargetException().getMessage());
        }

    }

    // --------------------------------------------------------- Public Methods

    /**
     * Return the Class object we will use to create new instances in the
     * <code>newInstance()</code> method. This Class <strong>MUST</strong>
     * implement the <code>DynaBean</code> interface.
     *
     * @return The class of the {@link DynaBean}
     */
    public Class<?> getDynaBeanClass(){

        return (this.dynaBeanClass);

    }

    // ------------------------------------------------------ Protected Methods

    /**
     * Set the Class object we will use to create new instances in the
     * <code>newInstance()</code> method. This Class <strong>MUST</strong>
     * implement the <code>DynaBean</code> interface.
     *
     * @param dynaBeanClass
     *            The new Class object
     *
     * @throws IllegalArgumentException
     *             if the specified Class does not
     *             implement the <code>DynaBean</code> interface
     */
    protected void setDynaBeanClass(final Class<?> dynaBeanClass){

        // Validate the argument type specified
        if (dynaBeanClass.isInterface()){
            throw new IllegalArgumentException("Class " + dynaBeanClass.getName() + " is an interface, not a class");
        }
        if (!DynaBean.class.isAssignableFrom(dynaBeanClass)){
            throw new IllegalArgumentException("Class " + dynaBeanClass.getName() + " does not implement DynaBean");
        }

        // Identify the Constructor we will use in newInstance()
        try{
            this.constructor = dynaBeanClass.getConstructor(constructorTypes);
        }catch (final NoSuchMethodException e){
            throw new IllegalArgumentException("Class " + dynaBeanClass.getName() + " does not have an appropriate constructor");
        }
        this.dynaBeanClass = dynaBeanClass;

    }

    /**
     * Set the list of dynamic properties supported by this DynaClass.
     *
     * @param properties
     *            List of dynamic properties to be supported
     */
    protected void setProperties(final DynaProperty[] properties){

        this.properties = properties;
        propertiesMap.clear();
        for (DynaProperty propertie : properties){
            propertiesMap.put(propertie.getName(), propertie);
        }

    }

}
